1. Field of the Invention
The present invention relates to a system for optically transmitting a frequency-division multiplex signal over a single optical waveguide, and more particularly to the transmission of a side band signal.
2. Description of the Prior Art
The problem of transmission of a frequency-division multiplex signal occupying a wide frequency band arises, for example in cable television transmission. In this example, a multiplicity of signals, each of which contains a television or radio program, must be transmitted.
A system for providing such transmission is known from German Patent Application A1 32 03 785, FIG. 4. In the known system, the whole frequency-division multiplex signal is transmitted by means of a single optical waveguide through the fact that several transmission frequency bands are formed, each of these transmission frequency bands is converted to an optical signal with its own wavelength, and the optical signals are transmitted in the wavelength multiplex mode via the optical waveguide. On the reception side, a reverse processing operation is carried out. The first part of the transmitting unit divides the originally wide frequency band and thus forms the transmission frequency bands. In the known process, it is not indicated how the different transmission frequency bands are to be selected, so that they will have the bandwidth suitable for the various optical transmitters.